Moderna’s Melanoma Shot Still Has One Hard Number: 49%. Phase 3 Hasn’t Printed.
The last confirmed success on Moderna and Merck’s melanoma vaccine is the five-year Phase 2b print: 49% less recurrence or death versus Keytruda alone. Phase 3 is enrolled. Today is not a new trial day. Trade that distinction.
The sentence making the rounds is that Moderna and Merck’s melanoma vaccine “succeeded” and the stock ripped. The last time that sentence was strictly true on a new data drop was January 20, 2026, when the companies put five-year follow-up from Phase 2b KEYNOTE-942 on the tape. Intismeran autogene (mRNA-4157 / V940) plus Keytruda cut the risk of recurrence or death by 49% versus Keytruda alone (HR 0.510, 95% CI 0.294–0.887). ASCO in June repeated it in public: 157 patients, high-risk resected stage III/IV melanoma, median five years. Distant-met risk was reported 59% lower in that update. Shares jumped 7.19% the morning after the January release, to $46.09 on one contemporaneous print. That is the surge we can document. We do not have a new trial press release dated today, and we are not going to write one.
What is live now is the wait. Phase 3 adjuvant melanoma — INTerpath-001, NCT05933577 — is fully enrolled. Moderna has said that pivotal readout is possible in 2026. Nine Phase 2 and 3 trials are running across melanoma, NSCLC, bladder, and kidney. The platform pitch is that COVID revenue is gone and oncology has to carry the equity story. Last close in the mid-$60s on Aug. 18 reporting is not a 50% gap. It is a name that already paid for the 49%.
What 49% is
It is a mid-stage, 157-patient result that held from three years to five. That is rare enough to matter. It is not FDA approval. It is not Phase 3. It is not a launch. Anyone conflating KEYNOTE-942 with a commercial melanoma franchise is selling a 2027 slide as a 2026 print.
Merck is in this for Keytruda’s next act. Moderna is in this because the COVID franchise does not pay the bills. Both incentives are public. The next number that can change the multiple is INTerpath-001, not another recap of the 49%.
How to sit MRNA from here
If you want the vaccine story, you are holding through a Phase 3 print that has not landed. If you want a day-trade off “trial succeeds,” you needed January — or June at ASCO. Today’s headline, without a new release, is recycling. We would rather say that out loud than dress a 7-month-old HR as breaking news.
The honest takeaway: the melanoma shot succeeded in Phase 2b at five years. Phase 3 is the live catalyst. There is no new trial success dated Aug. 19 in the public file we used.